[PATCH] tests/plugin/syscall.c: fix compiler warnings

[Juro Bystricky <juro.bystricky@intel.com>]

Fix compiler warnings. The warnings can result in a broken build.
This patch fixes warnings such as:

In file included from /usr/include/glib-2.0/glib.h:111,
                 from ../tests/plugin/syscall.c:13:
../tests/plugin/syscall.c: In function ‘print_entry’:
/usr/include/glib-2.0/glib/glib-autocleanups.h:28:3: error: ‘out’ may be
       used uninitialized in this function [-Werror=maybe-uninitialized]
   g_free (*pp);
   ^~~~~~~~~~~~
../tests/plugin/syscall.c:82:23: note: ‘out’ was declared here
     g_autofree gchar *out;
                       ^~~
In file included from /usr/include/glib-2.0/glib.h:111,
                 from ../tests/plugin/syscall.c:13:
../tests/plugin/syscall.c: In function ‘vcpu_syscall_ret’:
/usr/include/glib-2.0/glib/glib-autocleanups.h:28:3: error: ‘out’ may be
        used uninitialized in this function [-Werror=maybe-uninitialized]
   g_free (*pp);
   ^~~~~~~~~~~~
../tests/plugin/syscall.c:73:27: note: ‘out’ was declared here
         g_autofree gchar *out;
                           ^~~
cc1: all warnings being treated as errors

Signed-off-by: Juro Bystricky <juro.bystricky@intel.com>
---
 tests/plugin/syscall.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/tests/plugin/syscall.c b/tests/plugin/syscall.c
index 484b48de49..96040c578f 100644
--- a/tests/plugin/syscall.c
+++ b/tests/plugin/syscall.c
@@ -70,19 +70,17 @@ static void vcpu_syscall_ret(qemu_plugin_id_t id, unsigned int vcpu_idx,
         }
         g_mutex_unlock(&lock);
     } else {
-        g_autofree gchar *out;
-        out = g_strdup_printf("syscall #%" PRIi64 " returned -> %" PRIi64 "\n",
-                num, ret);
+        g_autofree gchar *out = g_strdup_printf(
+             "syscall #%" PRIi64 " returned -> %" PRIi64 "\n", num, ret);
         qemu_plugin_outs(out);
     }
 }
 
 static void print_entry(gpointer val, gpointer user_data)
 {
-    g_autofree gchar *out;
     SyscallStats *entry = (SyscallStats *) val;
     int64_t syscall_num = entry->num;
-    out = g_strdup_printf(
+    g_autofree gchar *out = g_strdup_printf(
         "%-13" PRIi64 "%-6" PRIi64 " %" PRIi64 "\n",
         syscall_num, entry->calls, entry->errors);
     qemu_plugin_outs(out);
-- 
2.27.0